1.Technical Field
The present invention generally relates to a method for testing color wheels, and particularly to a method for precisely measuring central angles of filter segments within a color wheel, along with an angular position of a timing mark on the color wheel.
2.Description of Related Art
Referring to FIGS. 7 and 8, a color wheel 10 of a projector system according to a related art is shown. The color wheel 10 includes a round color filter 100, a mounting portion 200, a motor 300 and a timing mark 400 adhered to a sidewall of the mounting portion 200. The color filter 100 is composed of three colored sector-shaped filter segments: a red filter segment 102, a green filter segment 104, and a blue filter segment 106. Because people perceive different colors at different response speeds, central angles of the red, green and blue filter segments 102, 104, 106 are designed to be different from each other. The timing mark 400 is arranged on the sidewall of the mounting portion 200.
While operating the projector system, the color filter 100 and the timing mark 400 are driven by the motor 300 to rotate together. The central angles of the filter segments 102, 104, 106 and the angular position of the timing mark 400 relative to the filter segments 102, 104, 106 can be detected to help the projector system recognize positions of the filter segments 102, 104, 106. In other words, the central angles of the filter segments 102, 104, 106 and the timing mark 400 help the projector system know which color is being displayed by the projector system at any given time. Therefore, the central angles of the filter segments 102, 104, 106 and the angular positions of the timing mark 400 are important parameters that influence the image quality produced by the projector system. If the central angles of the filter segments 102, 104, 106 and the actual angular position of the timing mark 400 relative to the filter segments 102, 104, 106 deviate significantly from the predetermined central angles of the filter segments 102, 104, 106 and predetermined angular position of the timing mark 400, the image quality of the projector system will be greatly degraded.